Design considerations for an electromagnetic railgun to be used against antiship missiles

Railguns can reach higher muzzle velocities and fire rates than conventional guns. Muzzle velocities up to 2400 m/s and fire rates of > 50 Hz have already been demonstrated with projectiles having a mass of 140 g and a square caliber of 25 mm². We investigated if a Close-In Weapon System (CIWS) based on a railgun performs better against incoming anti-ship missiles than a conventional CIWS such as the Goalkeeper. CIWS are operational systems that defend a ship against incoming subsonic antiship missiles. Future antiship missiles will be, however, supersonic and more difficult to defeat with conventional gun systems. Railguns are expected to perform better against these future threats thanks to their higher muzzle velocity and fire rate. We developed a simulation model calculating the hit probability of a burst of projectiles fired with muzzle velocities ranging from 1200 to 2400 m/s and fire rates ranging from 75 to 300 rounds/s. The target velocity ranges from subsonic (300 m/s) to supersonic (600 m/s). The performance requirements for a corresponding railgun are used to discuss possible system layouts. The kinetic energy to be delivered by the launcher translates into requirements for the pulsed power supply. However, thermal management has to be considered for repetitive launching. Therefore, we carried out numerical simulations on the electrical and thermal behavior of various solutions and compare their advantages and drawbacks.